I think it is hubris to assume that there are no other life forms in space. I think there may be other beings we would consider intelligent, but they may not be anything like us and are likely too far away for us to ever find them until we develop ways to travel in space by lightspeed!
There is no evidence for extraterrestrial life at the present. On the other hand the universe is a vastly huge place and it is difficult to believe there is no other life out there. Have a look at the FERMI PARADOX.
Drakes equation suggest up to 2000 civilisations in the milky way galaxy alone. The SETI Institute attempts to make contact wirh possible alien civilisations through the use of radio transmitters, yet will the astonomically large distances between any other planets possible of sustaining complex life, coupled with relitivity and the speed of light being the 'unversal speed limit,' the time involved in the the travelling of the radio waves, the possiblity of making contact and getting a message in return is small when considering the instability of societies, along with the possibility of the other civilations not being developed enough to have discovered radio waves.
As for physical contact, the probabilities are futile, unless a quicker form of travel is discovered (worm holes, time dilation etc). Though if a method such as this has been discovered by an alien society, it is plausible that they may have made contact, though analysis of anecdotal evidence points to the unlikely- why would they not just come out and introduce themselves, and if they wanted to be covert and were that technologically advanced, they would be good enough not to get caught.
We don't know that yet.
Some people claim to have seen unidentified objects, but since there is no scientific proof, we don't know if we can believe the people.
Please comment if you find out something new...